Corrugated heat pipe

ABSTRACT

A corrugated heat pipe sealed at both ends is disclosed, having a longitudinally corrugated peripheral wall and containing operating liquid therein. The corrugated heat pipe comprises inside a rope-like tension member extending therethrough in its longitudinal direction and secured at both ends. The rope-like tension member has the effect of preventing the corrugated heat pipe from elongation due to the weight thereof when the pipe is inserted in the ground, thus eliminating the possibility of local flattening of the corrugated outer periphery or of breakage of the pipe. Further, even when the coefficient of thermal expansion of the rope-like tension member differs from that of the corrugated heat pipe, since the corrugated heat pipe has its outer periphery corrugated in a wavy form in the longitudinal direction, it can sufficiently absorb the thermal expansion of the rope-like tension member. Thus, the corrugated heat pipe will not be broken, even when the coefficient of thermal expansion of the corrugated heat pipe differes from that of the rope-like tension member.

This is a division of application Ser. No. 164.560, filed Mar. 7, 1988,now U.S. Pat. No. 4,836,275, granted June 6, 1989.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a corrugated heat pipe for conductingterrestrial heat onto the surface of the ground for utilizing it formelting snow, power generation and so forth.

2. Description of the Related Art

Heretofore, a corrugated heat pipe is used to conduct terrestrial heatonto the ground surface from hot water in the ground by heat conduction,without depriving the ground of hot water or steam. Several tens orhundreds rigid heat pipes of steel or alloy steel, each, for example of10 long are laid out at the installation site and connected one by one,using male and female screws, to obtain a single long heat pipe which isthen inserted in the ground. A pipe having this structure cansufficiently withstand the hanging load and also radial pressureexternally applied to it is the depth of the ground. This method ofinstallation, however, has problems as regards operability. Theoperation performed when the pipes are connected on the installationsite encounters great diffuculties depending on status and evironmentsof the installation site. Nevertheless, the installing method is used inwhich the pipes are connected on the installation site. This is becauseif a single long steel or alloy steel heat pipe is completed in factory,it can not be transported to the installation site, because of its sizeand weight. There has been a proposal for improving the operability onthe site. This proposal is to provide a heat pipe having flexibility andreduced wall thickness. If a single long corrugated heat pipe havingflexibility and reduced wall thickness is completed in factory, it canbe readily transported to the installation site by winding it onto adrum. In addition, the flexible material is very light in weightcompared to steel or alloy steel. The flexible heat pipe is used asthermal siphon and is buried in the ground by inserting it into theground to a depth of 200 to 5,000 m.

However, this method has the following problems.

Since a pipe as long as several hundred to several thousand meters isburied such that it is suspended at the ground surface into the ground,it is subject to elongation due to its own weight, resulting inflattening of its corrugated outer peripheral surface or breakage of it.The flattening of the corrugated outer peripheral surface leads tofluctuations of the heat transfer characteristics in the longitudinaldirection.

When in the ground, the pipe is liable to be crushed due to a radialexternal pressure applied to it. Generally, the pipe experiences as highpressure as 0.12 kg/cm² multiplied by the depth in meters. In the depthof several thousand meters, the pipe experiences an external pressure ofseveral hundred kg/cm², so that it will be crushed if it has reducedwall thickness.

To solve the above problems, in the case of a power cable used for amining pit, a steel wire is wound closely helically on the entire outerperiphery of the inner sheath, and the helically wound steel wire iscovered by an outer sheath of vinyl or polyethylene. In this case,however, the handling of a hanger at the top of heat pipe is a verydifficult operation. In addition, when the heat pipe provided with thismeans is insertedly buried in the ground, its flexibility is spoiled dueto its very great weight. Further, the use of the vinyl or polyethylenesheath gives rise to the problems of the resistance against theterrestrial heat at high temperatures of 200° C. or above and reductionof the heat conductivity.

SUMMARY OF THE INVENTION

The present invention has been intended in the light of the above, andit has an object of providing a corrugated heat pipe, which can beinsertedly buried in the ground without possibility of elongation due tothe weight, leading to flattening of its corrugated outer periphery orits breakage.

Another object of the invention is to provide a corrugated heat pipe,which will not be crushed by externally applied radial pressure when itis insertedly buried in the ground.

According to the invention, there is provided a corrugated heat pipesealed at both ends, having a longitudinally corrugated peripheral walland containing operating liquid therein, which corrugated heat pipeincludes inside a rope-like tension member extending through it in itslongitudinal direction and secured at both ends. The rope-like tensionmember has an effect of preventing the corrugated heat pipe fromelongating due to the weight thereof when the pipe is inserted in theground, thus eliminating the possibility of local flattening of thecorrugated outer periphery or of breakage of the pipe. Further, evenwhen the coefficient of thermal expansion of the rope-like tensionmember differes from that of the corrugated heat pipe, since thecorrugated heat pipe has its outer periphery corrugated in a wavy formin the longitudinal direction, it can sufficiently absorb the thermalexpansion of the rope-like tension member. Thus, the corrugated heatpipe will not be broken, even when the coefficient of thermal expansionof the corrugated heat pipe differes from that of the rope-like tensionmember.

Further, according to the invention, a helical reinforcing member isprovided in contact with the inner wall of the corrugated heat pipe overthe entire length thereof or portions of the length. Thus, even when aradial pressure is externally applied to the corrugated heat pipeinserted in the ground, the pipe will never be crushed. The direction ofthe helical winding of the helical reinforcing member is the same asthat of the helical corrugation of the corrugated heat pipe. The pitchof the helical winding of the helical reinforcing member is the same asor smaller than that of the helical corrugation of the corrugated heatpipe. With this arrangement, the flexibility of the heat pipe is notspoiled, and the pipe can sufficiently absorb the thermal expansion ofthe rope-like tension member. Where the direction of the helical windingof the helical reinforcing member is opposite to the direction of thehelical corrugation of the corrugated heat pipe, the helical winding ofthe helical reinforcing member may have any desired pitch. In this case,effects obtainable where the helical winding of the reinforcing memberand helical corrugation of the corrugated heat pipe are in the samedirection, can be obtained without the reinforcing member received inthe groove of the pipe corrugation.

Still further, according to the invention a liquid condensate receptacleis attached on a rope-like tension member extending through thecorrugated heat pipe in the longitudinal direction thereof. The liquidcondensate receptacle receives liquid condensate cooled in and droppedfrom an upper portion of the pipe. The liquid received in the receptacleis evaporated toward the pipe upper portion. This has an effect ofpreventing the pipe upper portion from drying. Further, according to theinvention a wick presenting a capillarity is provided on the rope-liketension member extending longitudinally through the corrugated heat pipeover the entire length of the member or portions of the length. The wickcan retain liquid condensate, and the retained liquid condensate isevaporated toward the pipe upper portion to prevent the pipe upperportion from drying.

Furthermore, according to the invention a rope-like tension membersecured at both ends is provided along the outer peripheral surface ofthe corrugated heat pipe in the longitudinal direction thereof. Therope-like tension member support the weight of the corrugated heat pipewhen the pipe is inserted in the ground to prevent the pipe fromelongating due to the weight thereof, thus preventing the corrugatedouter periphery of the pipe from locally flattening or breading.

Further, according to the invention there is provided a corrugated heatpipe sealed at both ends, having a longitudinally corrugated peripheralwall, containing operating liquid therein, and a rope-like tensionmember extending through it in its longitudinal direction and secured atboth ends, which corrugated heat pipe includes a supporting memberdisposed between a portion of the rope-like tension member and arecessed inner wall portion of it to let the weight of the corrugatedheat pipe be supported between the rope-like tension member portion andrecessed inner wall portion. The weight of the corrugated heat pipe issupported by the supporting member and transferred to the rope-liketension member so that it is supported thereby. More specifically, asupporting member, which is composed of helical or ring-like wire memberor helical or disk-like plate member suited to the shape of the wavygroove of the corrugated heat pipe inner wall, is provided between therope-like tension member and the wavy groove of the corrugated heat pipeinner wall in the longitudinal direction of the pipe. The weight of thecorrugated heat pipe is supported by the supporting member andtransferred to the rope-like tension member, so that it is supportedthereby. Since the weight of the corrugated heat pipe is supported bythe supporting member when the pipe is inserted in the ground, it ispossible to prevent the pipe from elongating due to the weight thereof,thus preventing the corrugated outer periphery of the pipe from locallyflattening or breaking.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view showing an embodiment of thecorrugated heat pipe according to the invention;

FIG. 2 is a schematic sectional view, to a reduced scale, showing thecorrugated heat pipe of FIG. 1 in a state mounted in an on-groundbuilding structure;

FIG. 3 is a schematic elevational sectional view showing a differentembodiment of the corrugated heat pipe according to the invention;

FIG. 4 is a schematic side sectional view showing the corrugated heatpipe of FIG. 3;

FIG. 5 is a schematic fragmentary view showing a modification of thecorrugated heat pipe of FIGS. 3 and 4 with a wire member wound on thepipe at the pitch of the helical corrugation of the pipe periphery;

FIG. 6 is a sectional view taken along line VI--VI in FIG. 5 and viewedin the direction of arrow;

FIG. 7 is a schematic fragmentary view showing a different modificationof the corrugated heat pipe of FIGS. 3 and 4, in which rope-like tensionmembers are held in close contact with the pipe outer periphery by apreformed wire member;

FIG. 8 is a sectional view taken along line VIII--VIII in FIG. 7 andviewed in the direction of arrow;

FIG. 9 is a schematic fragmentary view showing a further modification ofthe corrugated heat pipe of FIGS. 3 and 4, in which rope-like tensionmembers are held in close contact with the pipe outer periphery byhinged strip-like members;

FIG. 10 is a sectional view taken along line X--X in FIG. 9 and viewedin the direction of arrow;

FIG. 11 is a schematic elevational sectional view showing a furtherembodiment of the corrugated heat pipe according to the invention; and

FIGS. 12 to 15 are perspective views showing respective examples of asupporting member used for the corrugated heat pipe of FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, preferred embodiments of the corrugated heat pipe according to theinvention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic sectional view showing an embodiment of thecorrugated heat pipe according to the invention, and FIG. 2 shows thecorrugated heat pipe of FIG. 1 in a state mounted in an on-groundstructure. In FIG. 2, the inner arrangement of the corrugated heat pipeis shown in a simplified form compared to FIG. 1 for the sake ofsimplicity.

Corrugated heat pipe 1 as shown, has flexibility, and its upper portionincluding a hanger portion extends on the ground. Its main portion isinserted substantially vertically in the ground 100. Usually, thecorrugated heat pipe is inserted into a depth of 200 to 3000 m.

The corrugated heat pipe is made of such metal as steel, copper,aluminum and stainless steel and has an inner diameter of 50 to 300 mm.Its peripheral wall 101 is wavy, i.e., corrugated, in the longitudinaldirection. The corrugated heat pipe contains therein operating liquid102, e.g., "Furon" (a trademark).

The form of corrugation of peripheral wall 101 may be either helical ornon-helical, e.g., bellows-like.

Rope-like tension member 2, which is composed of stranded steel or likewires, is provided inside the sealed corrugated heat pipe, and extendscoaxially therethrough, and its upper and lower ends are fittedlysecured in center holes in upper and lower end securement members 201and 202 provided at the upper and lower ends of the corrugated heatpipe. Actually, the ends of rope-like tension member 2 are secured tothe end securement members by means of press clamping, welding, etc. Theoperation of securement is done in factory. The rope-like tension member2 may be a stranded rope of fine steel wires, a hempen rope, a strandedrope of fine plastic fibers, a stranded rope of fine carbon fibers, orthe like. Upper end securement member 201 has a disk-like sealingportion having a central hole and a coaxial cylindrical boss portionalso having a central hole. A portion of the rope-like tension memberinserted in the central hole of the sealing portion is welded to orscrewedly coupled to the same, whereby the upper end of corrugated heatpipe 1 is sealed. A portion of the rope-like tension member inserted inthe central hole of the boss portion is secured to the same by means ofpress clamping, whereby a great hanging load of the corrugated heat pipeis supported.

Upper end securement member 201 is coaxially secured by means ofscrewing to hanger 203. Hanger 203 is provided with hole 204 formedtherein for facilitating the operation when the corrugated heat pipe istransported and installed.

The lower end of rope-like tension member 2, like the upper end, isinserted in the central hole of securement member 202 and secured tolower end thereof. The lower end of the corrugated heat pipe is thussealed.

The boss portion of lower end securement member 202 is protected by capmember 205. The means of securing the upper and lower ends of rope-liketension member 2 are not limitted to the above means.

Reinforcing member 3 is composed of a steel or like metal strip which iswound helically. It is mounted in contact with the inner wall ofcorrugated heat pipe 1 such that it will not slip down. Before it ismounted, it may be contracted by cooling, so that it may be expanded tothe normal size after the mounting. It may be mounted over the entirelength of the corrugated heat pipe or a portion of the length. It iseffective and desired that reinforcing member 3 is used for a portion ofthe corrugated heat pipe inner wall which is inserted deep in theground.

Where corrugated heat pipe 1 has a helical corrugation, the pitch ofhelical winding of reinforcing member 3 may be equal to or smaller thanthe pitch of helical corrugation of pipe 1. The metal strip constitutingreinforcing member 3 may have any sectional profile, e.g., a circular orangular profile, so long as the flexibility of corrugated heat pipe isnot spoiled.

Liquid condensate receptacle 4 is a member having a recess open upwardsuch as a dish or a cup. It may be attached on rope-like tension member2 by fitting its central hole thereon. Liquid condensate receptacles mayhave size and be used in number determined by taking the inner diameter,length and heat transport capacity of the corrugated heat pipe.Receptacle 4 may be attached on rope-like tension member 2 over theentire length thereof or a portion or portions. Further, they may beprovided closely or at an interval over the entire length or a portionor portions. They may be readily attached in factory.

Rope-like tension member 2 is not limitative as corrugated heat pipesupport means; for instance it is possible to use like rope extendingthrough the corrugated heat pipe.

Reference numeral 5 designates a wick. It is composed of a metal net orvery fine wires and provided suitably on rope-like tension member 2. Itmay be provided on rope-like tension member 2 over the entire lengththereof or a portion or portions. Further, it may be provided closely orat an interval over the entire length or a portion or portions.Furthermore, the wick may be constituted by rope-like tension member 2itself. Further, it may be buried in rope-like tension member 2.Further, it may be provided on a rope substituted for rope-like tensionmember 2 over the entire length thereof or a portion or portions.

Wick 6 which is provided between the inner wall of the corrugated heatpipe and reinforcing member 3 is composed of a metal net, fine wires,etc. It may be clamped between the inner wall of corrugated heat pipe 1and reinforcing member 3 by making use of the contact pressuretherebetween. Further, very fine wires may be preliminarily wound on themetal strip of reinforcing member, and then the resultant assembly maybe wound into a helical form having a predetermined number of turns,thus obtaining wick 6.

Wick 6, like wick 5, may be provided on the corrugated heat pipe innerwall over the entire length thereof or a portion or portions.

Evacuation/liquid supply nozzle 206 is provided for evacuating andsupplying liquid to corrugated heat pipe 1.

FIG. 2 shows corrugated heat pipe 1 of FIG. 1 which is secured to andsupported by on-ground building structure 10.

Reference numeral 11 designates a terrestrial heat conducting pipe,through which the terrestrial heat is transferred to a cooler (notshown). Reference numeral 12 designates a return pipe, through whichliquid condensate produced as a result of cooling in the cooler isrecirculated to corrugated heat pipe 1. Reference numeral 13 designatesa branch pipe, which is used for evacuation, exhausting as well as theoperation and monitoring of pressure gauges, safety valves, etc.

Corrugated heat pipe 1 may be provided with local heat insulation and/orcorrosion-proof or other protective treatment, if necessary.

FIGS. 3 and 4 illustrate a different embodiment of the invention. Inthese Figures, parts like those in FIGS. 1 and 2 are designated bycorresponding reference numerals, and their detailed description isomitted.

In the previous embodiment of FIGS. 1 and 2, the rope-like tensionmember is provided inside the corrugated heat pipe. In this embodiment,rope-like tension members 2 are provided outside the corrugated heatpipe. Rope-like tension members 2 are composed of steel wire stands andextend along the outer peripheral surface of corrugated heat pipe 1 inthe longitudinal direction thereof. Their lower end is secured by meansof press clamping to lower end securement member 202 of corrugated heatpipe. The securing operation may be done in factory. Their upper portionprojected from the ground surface is clamped by clamp 16. Rope-liketension members 2 are supported by on-ground building structure 10 viaclamp 16.

One or more (practically four or more) rope-like tension members 2 areused depending on the size and weight of corrugated heat pipe 1. Thenumber of rope-like tension members provided on the outer peripheralsurface of corrugated heat pipe 1 and also the number and diameter ofstranded wires, are suitably selected depending on desired mechanicalstrength. Since a plurality of rope-like tension members are provided onthe outer peripheral surface of corrugated heat pipe 1, their inspectionand maintenance may be readily done even in the event of occurrence ofdamage to some of them.

Reference numeral 18 designates a wire, which is a solid or strandedmetal wire. As shown in FIG. 5, it is wound helically and continuouslyon the outer peripheral surface of corrugated heat pipe 1 over anecessary length thereof at a substantially constant pitch, wherebyrope-like tension members 2 are held in close contact with the peripheryof pipe 1. Where periphery of corrugated heat pipe 1 is corrugatedhelically, wire 18 is drawn with tensile force P (as shown in FIG. 6)while adjusting its position such that it is accommodated in helicalgroove 19 of corrugation at the pitch thereof. The ends of wire 18 thuswound are treated by suitable available means so that the wire will notbecome loose. Wire 18 may be wound at a constant pitch, i.e., at thesame pitch as the pitch of corrugation of the corrugated heat pipe, orthe pitch may be reduced so that the wire is wound more closely wherethe own weight is greatly supported.

Further, wire 18 may be wound helically, or it may be wound helically inone direction and then in the opposite direction so that it turnsoverlap. Where corrugated heat pipe 1 has a bellows-like corrugation,wire 18 of course may be wound either helically or nonhelically.

The various components of the corrugated heat pipe may be mounted infactory or in the site of installation. A portion of the corrugated heatpipe extending from the ground surface is connected to cooler 20.Operating liquid 102, which is sealed under a reduced pressure conditionin the corrugated heat pipe (FIG. 5), repeats a cycle of beingevaporated by the terrestrial heat to enter cooler 20 and transfer itsheat thereto, thus being condensed into liquid to be recirculated to thebottom of the corrugated heat pipe for evaporation again.

FIGS. 7 and 8 illustrate a modification of the corrugated heat pipeshown in FIGS. 5 and 6.

In this modification, rope-like tension members are held in closecontact with corrugated heat pipe 1 by a preformed helical wire. Morespecifically, like the embodiment of FIGS. 3 to 6, preformed helicalwire 31 in a helical form at a substantially constant pitch and having asuitable length is wound on the outer peripheral surface of corrugatedheat pipe 1 as means for holding rope-like tension members 2 extendingalong the outer periphery of pipe 1 in the longitudinal directionthereof in close contact with pipe 1. Preformed helical wire 31 is madeof a metal having comparatively high spring characters, e.g., steel ornon-ferrous metals or alloys. The helical winding of wire 31 has aninner diameter slightly smaller than the outer diameter of corrugatedheat pipe 1 inclusive of rope-like tension members 2. In this case, whenwire 31 is fitted manually, an adequate spring pressure is provided toeliminate slip between rope-like tension member 2 and corrugated heatpipe 1. If necessary, a plurality of preformed helical wires 31 may beused such that they are assembled in advance into a strip-like form.Further, the inner side of the helical winding of wire may be sanded toprovide enhanced frictional force. In this case, it is possible toprevent slip between preformed helical wire 31 and corrugated heat pipe1 and effectively support the weight of the corrugated heat pipe. Suchpreformed helical wire 31 need not be provided over the entire length ofpipe 1, but it may be provided on suitable portion of pipe 1 in thelongitudinal direction thereof (for instance at a longitudinal intervalof 5 m). Thus, preformed helical wire 31 may be readily mounted at theinstallation site. In this case, the wire may be provided at a constantinterval as in the embodiment of FIG. 7, but it may be provided moreclosely where much weight is supported.

Preformed helical wire 31 may be suitably provided irrespective ofwhether the periphery of corrugated heat pipe 1 has a helical orbellows-like corrugation.

FIGS. 9 and 10 show a modification of the embodiment of FIGS. 3 to 6. Inthis case, hinged strip-like members are used as means for holding therope-like tension members in close contact with the corrugated heatpipe.

More specifically, in this case strip-like members 33 each with hinge 32are used. Each strip-like member 35 is set to surround corrugated heatpipe 1 and rope-like tension members and then clamped by turning screw34 to reduce clamping gap 35. It is made of such material as steel ornon-ferrous metals or alloys. It has substantially the same inner shapeand diameter as the outer diameter of corrugated heat pipe 1 inclusiveof rope-like tension members 2. It comprises two halves hinged togetherby hinge 32, and it is secured to corrugated heat pipe 1 in asurrounding state by clamping it with screw 34 at clamping gap 35. Sincestrip-like members 33 are clamped, no slip is produced between rope-liketension members and corrugated heat pipe. Strip-like members 33 may beprovided on corrugated heat pipe 1 at suitable portions thereof in thelongitudinal direction (for instance at an interval of 5 m). Therefore,the operation of holding the rope-like tension members in close contactwith the corrugated heat pipe may be readily done at the installationsite. Instead of strip-like member 33, two striplike members without anyhinge may be used. In this case, the two strip-like members are set faceto face on the pipe outer periphery, and their opposed edges are clampedwith screws at clamping gaps. Further, it is possible to use astrip-like member set which comprises of more than two separatesections.

FIGS. 11 and 12 illustrate a further embodiment of the invention. Inthese Figures, parts like or corresponding to those in the embodiment ofFIG. 1 are designated by corresponding like reference numerals, andtheir description is omitted.

In this embodiment, supporting wire 43 is used instead of thereinforcing member in the embodiment of FIG. 1. Supporting wire 43 is anelastic or rigid wire, e.g., a steel wire. It is disposed helicallybetween and in close contact with rope-like tension member 2 andrecessed inner wall portion of corrugated heat pipe 1 (i.e., valleys ofcorrugation when viewed from the inner side of pipe 1).

More specifically, some of supporting wire 43 is helically wound onpredetermined portions of rope-like tension member 2 in the longitudinaldirection thereof, while the remainder is received in and held in closecontact with helically recessed inner wall 51 or valleys of corrugatedheat pipe 1.

Wick 53 is provided on some predetermined portions of supporting wire43. It may be provided over the entire length of supporting wire 43 orportions of the lengths.

FIG. 12 shows a way of securement of wick 53. In this case, wick 53 isheld secured in the recessed inner wall of the pipe by supporting wire43.

The length, for which supporting wire 43 is wound on rope-like tensionmember 2, and the length, for which the supporting wire is held in closecontact with the helical recessed inner surface of corrugated heat pipe2 (i.e., the product of the number n of turns in close contact and thepitch p), are suitably selected such that the weight of the corrugatedheat pipe is uniformly shared by the entire supporting wire. Forexample, the length, for which rope-like tension member 2 is held inclose contact with recessed inner wall 51 of pipe 1, may be equal to ortwice the pitch of corruagation of the corrugated heat pipe.

The distribution of the supporting wire is determined by taking the size(i.e., length and diameter) of corrugated heat pipe 1 and the geologyand terrestrial heat temperature distribution of the place of the pipeinstallation into considerations. The supporting wire may be providedover the entire length of rope-like tension member 2 or portionsthereof. Particularly, in the depth of the ground the supporting wire isdesirably disposed collectively for a great hanging load of the pipeapplied.

Further, the supporting member may be mounted in factory, or it may bemounted at the installation site by preparing a simple mounting device.In this case, the supporting member may be contracted in size by coolingit before mounting it.

Steam passes through gaps defined by the supporting members toward upperportion of the corrugated heat pipe, that is, without being blocked bythe supporting member, so that it is possible to ensure proper functionof the heat pipe.

FIG. 13 shows a further example of the supporting wire. In this case,the corrugated heat pipe (not shown), with which the supporting wire isheld in close contact, is corrugated bellows-like.

A portion of supporting wire 43 is wound on rope-like tension member 2,while the remainder is held in a ring-like form in the recessed innerperipheral wall of the pipe. In this case, opposite end portions C and D(FIG. 3) of a turn of supporting wire 43 are found at the same positionin the direction of extension of the rope-like tension member. In thiscase, the method of mounting and distribution of the supporting wire maybe the same as described before in conjunction with FIGS. 11 and 12.

Reference numeral 54 designates a supporting plate.

FIG. 14 shows supporting plate 54. It is substantially disk-like, and isformed from a metal plate, a plastic plate, etc. It has notch 61.Rope-like tension member 2 is closely fitted in inner end 62 of notch61, whereby the supporting plate is held in position without possibilityof slide-down. Supporting plate 54 has a helical outer periphery, whichis received and held in close contact with helical recessed inner wallof the corrugated heat pipe (not shown). As shown in FIG. 14, the outerperiphery of supporting plate 54 is inclined helically so that oppositeends A and B of notch 61 are spaced apart by a distance equal to thepitch P of the helical corrugation of the corrugated heat pipe.Supporting plate 54 is provided with holes 64 formed therein to permitpassage of steam. Holes 64 may have any suitable shape, e.g., circular,oval, flaring, etc. The method of mounting and distribution ofsupporting plates 54 may be the same as for supporting wire 43 in thecase of FIGS. 12 and 13.

FIG. 15 shows a different example of supporting plate. This supportingplate is provided in a corrugated heat pipe having a bellows-likecorrugation (not shown).

This example of supporting plate 75 is like a flat disk having notch 81.Rope-like tension member 2 is closely fitted in end 82 of supportingplate 75. The outer periphery of supporting plate 75 is closely mountedin a recessed inner peripheral wall of pipe. In this case, opposite endsE and F of notch 81 of supporting plate 75 are not spaced apart but atthe same position in the direction of extension of the rope-like tensionmember.

Supporting plate 75 has holes 84 for permitting passage of steam. Holes84 may have any suitable shape as in the case of FIG. 14.

Inside corrugated heat pipe 1, liquid condensate receptacle 4 having arecess open upward, e.g., like a cup or a dish, is attached on rope-liketension member 2. Further, wick 302 is attached on tension-resistantrope 2. The rope-like tension member itself may serve as wick instead ofparticularly providing wick 302. Further, the inner peripheral wall ofpipe is provided with wick 53.

In the above embodiment provided with the supporting member, there willhardly occur a slip-down between the corrugated heat pipe and supportingmember due to thermal expansion.

Liquid condensate will drop on the supporting member and temporarilyretained on this part. The retained or collected liquid on thesupporting member is evaporated toward upper portion of the pipe. Thishas an effect of preventing the upper portion of the pipe from drying.

Reference numeral 206 designates an evacuation/liquid supply nozzle forevacuating and supplying liquid to corrugated heat pipe 1.

The corrugated heat pipe, of course, is further provided with other,usually used accessory devices, e.g., a terrestrial heat conductingpipe, a liquid return pipe, branch pipes, etc. Further, corrugated heatpipe 1 is supported, if necessary, by an on-ground building structure,and also it may be partly provided with heat insulation, corrosion-proofand other protective treatments.

While the above embodiments have concerned with cases where thecorrugated heat pipe according to the invention is inserted verticallyin the ground. This is, however, by no means limitative. For example,the corrugated heat pipe may be installed in the sea, or it may beinstalled such that it is inclined with respect to the ground surface.For example, where there is an obstacle in the ground, it may beinstalled in an inclined state to avoid such obstacle. Further, it maybe installed horizontally. Where the corrugated heat pipe is installedhorizontally, when a force of longitudinal thermal expansion is exerted,the rope-like tension member has an effect of preventing the corrugatedheat pipe from elongaing and thus deforming. Thus, it is possible tomaintain satisfactory heat transfer characteristics.

As has been described in the foregoing, according to the invention it ispossible to provide an elongate heat pipe, which can be readilytransported. This elongate heat pipe can preclude low operability workson the installation site. Further, the elongate heat pipe may be factoryprovided with various components. With the functions of thesecomponents, it is possible to prevent the pipe from elongating due tothe weight thereof, particularly prevent the pipe from crushing due tohigh radial external pressure applied to its portion extending deep inthe ground, and also prevent an upper portion of the pipe from dryingowing to positive promotion of evaporation by the liquid condensatereceptacle, wick and other parts. Further, on the installation site, itis only necessary to insert and hang the corrugated heat pipe in a pitin the simplest case.

What is claimed is:
 1. A flexible corrugated heat pipe for conducting terrestrial heat, said heat pipe being sealed at both ends and containing an operating liquid therein, said heat pipe comprising:a longitudinally corrugated peripheral wall for rendering the heat pipe flexible; a reinforcing member provided on an inner peripheral wall surface of a corrugated portion of said heat pipe; said reinforcing member extending along at least a portion of the length of said heat pipe and spanning over a plurality of corrugations of said peripheral wall; an elongated rope-like tension member extending through said heat pipe and secured at end portions of said heat pipe; and wick means provided between said reinforcing member and said inner peripheral wall surface of said heat pipe.
 2. The flexible corrugated heat pipe of claim 1, wherein corrugations of said peripheral wall extend circumferentially around the heat pipe, and are spaced along the length of said heat pipe.
 3. The flexible corrugated heat pipe of claim 1, wherein said wick means is coupled to and supported by said elongated rope-like tension member. 